Yes, that was a rabbit inside a refrigerator. In 1943, the maker of Coolerator Refrigerator decided to use a cute bunny locked inside the food compartment to tout the appliance's selling point:

This "contented rabbit" lived in the food compartment of a Coolerator Refrigerator throughout the recent Furniture Market show in Chicago to demonstrate that there is a constantly changing flow of pure, fresh air within an ICE Refrigerator which is sufficient to sustain life. Because the current of air passing through the ice compartment was constantly purified and refreshed as it passed over the Ice, the rabbit lived in comfort, although the door was tightly closed....